Submarine cable aging detection method and device based on flexoelectric effect
By acquiring the polarization charge generated by the submarine cable under non-uniform strain and calculating the flexural coefficient, the problems of lag and low accuracy in submarine cable aging detection are solved, and real-time and accurate assessment of submarine cable aging is realized.
Patent Information
- Application Number
- CN202511993745.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-02-27
AI Technical Summary
Existing methods for detecting aging of submarine cables suffer from delays and low accuracy, making it difficult to meet the high safety and reliability requirements of offshore wind power systems.
By acquiring the polarization charge generated by the submarine cable under non-uniform strain when it is in a power-off state, and calculating the flexural coefficient using the flexural effect theory, the aging degree of the submarine cable is evaluated in real time in combination with structural parameters, and an alarm is issued.
It achieves real-time and accurate detection of submarine cable aging, and can promptly reflect changes in the electrical performance of the cable, solving the problems of lag and low accuracy of traditional detection methods.
Smart Images
Figure CN121578022A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of electrical equipment maintenance, and in particular to a submarine cable aging detection method and device based on flexoelectric effect. BACKGROUND
[0002] At present, the submarine cable aging evaluation technology of offshore wind power platform mainly relies on traditional methods such as physical inspection and mechanical damage detection. These methods have certain effect in long-term operation and maintenance, but their limitations are increasingly prominent, especially in realizing real-time and accurate aging state evaluation.
[0003] The traditional evaluation method takes visual inspection as the core, that is, relying on professional personnel to regularly approach the submarine cable by ship or auxiliary platform, observing its appearance changes through visual observation or auxiliary tools, and judging whether there are obvious aging marks such as surface cracks, sheath wear and structure deformation. This method highly depends on the experience and subjective judgment of the inspectors, and is greatly affected by the marine environmental conditions. Bad weather, low visibility, and sea wave surge will seriously affect the feasibility and accuracy of the inspection. In addition, visual inspection can only find the damage that has developed to the outside, and it is difficult to detect latent defects such as internal insulation aging, water tree generation and fatigue micro-cracks, so the risk of missed detection is high. In addition to manual inspection, mechanical damage detection mainly relies on regular sampling inspection or event-triggered inspection, which is not comprehensive, and it is difficult to quantitatively evaluate the long-term fatigue state of the submarine cable under complex marine dynamic environment.
[0004] In summary, the existing submarine cable aging detection methods generally have the problems of hysteresis and low accuracy, which are difficult to meet the high requirements of safety and reliability of offshore wind power systems. SUMMARY
[0005] The present application provides a submarine cable aging detection method and device based on flexoelectric effect, which can solve the problems of hysteresis and low accuracy existing in the existing submarine cable aging detection methods.
[0006] An embodiment of the present application provides a submarine cable aging detection method based on flexoelectric effect, comprising: obtaining the polarization charge generated by the submarine cable to be detected under non-uniform strain in a power-off state, and the structural parameters of the submarine cable to be detected; amplifying the polarization charge, and forming a voltage waveform according to the voltage signal of the amplified polarization charge; calculating the flexoelectric coefficient of the submarine cable to be detected according to the voltage waveform and the structural parameters; determining the aging degree of the submarine cable to be detected according to the flexoelectric coefficient, and issuing an alarm when the aging degree is greater than a preset degree threshold.
[0007] Furthermore, calculating the flexural conductivity of the submarine cable under test based on the voltage waveform and the structural parameters includes: Obtain the amplification gain coefficient of the polarization charge; Based on the voltage waveform, determine the voltage peak value, and calculate the polarization charge based on the amplification gain coefficient and the voltage peak value; The flexural conductivity of the submarine cable under test is calculated based on the polarization charge and the structural parameters.
[0008] Furthermore, the structural parameters include: the outer radius of the insulation layer of the submarine cable under test, the bending angle, the length of the bending section, and the dielectric constant of the insulation layer; The step of calculating the flexural conductivity of the submarine cable under test based on the polarization charge and the structural parameters includes: The strain gradient and effective stress area of the submarine cable under test are calculated based on the outer radius of the insulation layer, the bending angle, and the length of the bending segment. The flexural coefficient of the submarine cable under test is calculated based on the polarization charge, the dielectric constant, the strain gradient, and the effective stress area.
[0009] Furthermore, determining the degree of aging of the submarine cable under test based on the flexural conductivity includes: Obtain a flexural conductivity comparison table; wherein, the flexural conductivity comparison table records the standard flexural conductivity of the unaged submarine cable under test at different bending angles; Based on the bending angle, the target flexural coefficient is determined by searching the flexural coefficient lookup table. The difference between the target flexural coefficient and the flexural coefficient is calculated, and the degree of aging of the submarine cable to be tested is determined based on the difference.
[0010] Furthermore, the construction of the flexural coefficient lookup table includes: Construct a simulation model of the submarine cable to be tested in its unaged state; In a simulation environment, the standard flexural conductivity of the simulation model at different bending angles is measured; Based on the bending angle and the corresponding standard flexural conductivity coefficient, a flexural conductivity coefficient reference table is constructed.
[0011] An embodiment of the present invention also provides a submarine cable aging detection device based on flexural electrical effect, comprising: a calculator, an oscilloscope, and a charge amplifier; The input terminal of the charge amplifier is connected to the submarine cable under test, the input terminal of the oscilloscope is connected to the output terminal of the charge amplifier, and the input terminal of the calculator is connected to the output terminal of the oscilloscope; wherein the submarine cable under test is in a power-off state; The charge amplifier is used to receive the polarization charge generated by the submarine cable under non-uniform strain and amplify the polarization charge. The oscilloscope is used to receive the amplified voltage signal of the polarized charge and form a voltage waveform; The calculator is used to obtain the structural parameters of the submarine cable; calculate the flexural conductivity of the submarine cable under test based on the voltage waveform and the structural parameters; determine the aging degree of the submarine cable under test based on the flexural conductivity, and issue an alarm when the aging degree is greater than a preset degree level threshold.
[0012] Furthermore, the calculator calculates the flexural conductivity of the submarine cable under test based on the voltage waveform and the structural parameters, including: Obtain the amplification gain coefficient of the polarization charge; Based on the voltage waveform, determine the voltage peak value, and calculate the polarization charge based on the amplification gain coefficient and the voltage peak value; The flexural conductivity of the submarine cable under test is calculated based on the polarization charge and the structural parameters.
[0013] Furthermore, the structural parameters include: the outer radius of the insulation layer of the submarine cable under test, the bending angle, the length of the bending section, and the dielectric constant of the insulation layer; The calculator calculates the flexural conductivity of the submarine cable under test based on the polarization charge and the structural parameters, including: The strain gradient and effective stress area of the submarine cable under test are calculated based on the outer radius of the insulation layer, the bending angle, and the length of the bending segment. The flexural coefficient of the submarine cable under test is calculated based on the polarization charge, the dielectric constant, the strain gradient, and the effective stress area.
[0014] Furthermore, the calculator determines the degree of aging of the submarine cable under test based on the flexural conductivity coefficient, including: Obtain a flexural conductivity comparison table; wherein, the flexural conductivity comparison table records the standard flexural conductivity of the unaged submarine cable under test at different bending angles; Based on the bending angle, the target flexural coefficient is determined by searching the flexural coefficient lookup table. The difference between the target flexural coefficient and the flexural coefficient is calculated, and the degree of aging of the submarine cable to be tested is determined based on the difference.
[0015] Furthermore, the construction of the flexural coefficient lookup table includes: Construct a simulation model of the submarine cable to be tested in its unaged state; In a simulation environment, the standard flexural conductivity of the simulation model at different bending angles is measured; Based on the bending angle and the corresponding standard flexural conductivity coefficient, a flexural conductivity coefficient reference table is constructed.
[0016] The following benefits can be obtained by implementing the present invention: This invention provides a method and apparatus for detecting submarine cable aging based on the flexural effect. The method involves acquiring the polarization charge generated by the submarine cable under test in a de-energized state under non-uniform strain, along with the cable's structural parameters. The polarization charge is amplified, and a voltage waveform is generated based on the amplified voltage signal. Based on the flexural effect theory—that is, the generation of polarization charge in insulating materials under non-uniform strain—this invention measures and amplifies the polarization charge generated by the submarine cable under non-uniform strain to detect minute charge changes caused by variations in the cable's electrical characteristics, capturing the electrical response waveform of the cable under bending conditions in real time. Furthermore, the flexural coefficient of the submarine cable is calculated based on the voltage waveform and the structural parameters. The degree of aging of the cable is determined based on the flexural coefficient, and an alarm is issued when the aging degree exceeds a preset threshold. Therefore, this invention directly calculates the flexural coefficient, which reflects changes in the cable's electrical performance, thereby accurately and in real-time assessing the cable's aging degree, effectively solving the problems of lag and low accuracy in existing submarine cable aging detection methods. Attached Figure Description
[0017] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0018] Figure 1 This is a schematic flowchart of a submarine cable aging detection method based on flexural electrical effect provided in a certain embodiment of this application; Figure 2 This is a schematic diagram of a submarine cable aging detection device based on the flexural electrical effect provided in a certain embodiment of this application. Detailed Implementation
[0019] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.
[0021] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.
[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0023] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.
[0024] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).
[0025] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.
[0026] See Figure 1 To address the problems in the prior art, an embodiment of the present invention provides a method for detecting the aging of submarine cables based on the flexural electrical effect, comprising: S1. Obtain the polarization charge generated by the submarine cable under test in a power-off state under non-uniform strain, as well as the structural parameters of the submarine cable under test; In a preferred embodiment of the present invention, in an offshore wind farm, the section of the dynamic submarine cable located near the wind turbine is more susceptible to aging phenomena such as insulation deterioration due to the long-term influence of dynamic loads. Therefore, this section of the cable is selected as the testing target. During the testing process, the power supply to the submarine cable is disconnected to ensure that no current flows in the cable, avoiding electrical interference and ensuring that the testing is not affected by external electrical factors.
[0027] S2. Amplify the polarization charge and form a voltage waveform based on the voltage signal of the amplified polarization charge; In a preferred embodiment of the invention, a charge amplifier is used to amplify the polarization charge. The charge amplifier amplifies minute charge changes caused by variations in the electrical characteristics of the cable, providing necessary signal enhancement. The output terminal of the charge amplifier is connected to an oscilloscope or other waveform analysis equipment to capture the electrical response waveform of the cable under bending conditions in real time. Through waveform analysis, changes in the electrical characteristics of the cable can be monitored in real time.
[0028] S3. Calculate the flexural conductivity of the submarine cable under test based on the voltage waveform and the structural parameters. Preferably, the step of calculating the flexural conductivity of the submarine cable under test based on the voltage waveform and the structural parameters includes: S31. Obtain the amplification gain coefficient of the polarization charge; S32. Determine the voltage peak value based on the voltage waveform, and calculate the polarization charge based on the amplification gain coefficient and the voltage peak value; In a preferred embodiment of the present invention, firstly, the peak voltage Vpeak output by the charge amplifier is read using an oscilloscope; secondly, the polarization charge is calculated based on the amplification gain coefficient of the charge amplifier. Q = Vpeak / G; Where G is the amplification gain coefficient, in units of V / pC or V / C; and Q is the polarization charge.
[0029] S33. Calculate the flexural coefficient of the submarine cable to be tested based on the polarization charge and the structural parameters.
[0030] Preferably, the structural parameters include: the outer radius of the insulation layer of the submarine cable to be tested, the bending angle, the length of the bending section, and the dielectric constant of the insulation layer; The step of calculating the flexural coefficient of the submarine cable under test based on the polarization charge and the structural parameters includes: calculating the strain gradient and effective stress area of the submarine cable under test based on the outer radius of the insulation layer, the bending angle, and the length of the bending segment; and calculating the flexural coefficient of the submarine cable under test based on the polarization charge, the dielectric constant, the strain gradient, and the effective stress area.
[0031] In a preferred embodiment of the present invention, for a cylindrical cable at a bending angle θ (radians), the strain gradient on its outer surface can be approximated as: ; Where r is the outer radius of the cable insulation layer (m); is the bending angle (radians); L is the length of the bent segment (m). Furthermore, for cable insulation, the effective stress-bearing area is taken as the projected area of the bending cross-section: ; When θ is small, it can be simplified to: ; Substitute the above parameters into the following formula: ; After simplification, we get: ; To facilitate rapid on-site evaluation, simplified calculation formulas from practical applications are typically used. These simplified formulas can be established through system calibration. in, The system calibration constant is obtained by calibrating a standard sample with a known flexural coefficient in the same test system.
[0032] S4. Determine the degree of aging of the submarine cable to be tested based on the flexural coefficient, and issue an alarm when the degree of aging exceeds a preset threshold level.
[0033] Preferably, determining the degree of aging of the submarine cable under test based on the flexural conductivity includes: Obtain a flexural conductivity reference table; wherein the flexural conductivity reference table records the standard flexural conductivity of the unaged submarine cable to be tested at different bending angles; according to the bending angle, search the flexural conductivity reference table to determine the target flexural conductivity; calculate the difference between the target flexural conductivity and the flexural conductivity, and determine the degree of aging of the submarine cable to be tested based on the difference.
[0034] Preferably, the construction of the flexural coefficient lookup table includes: A simulation model of the submarine cable to be tested in its unaged state is constructed; in the simulation environment, the standard flexural conductivity of the simulation model at different bending angles is measured; based on the bending angles and the corresponding standard flexural conductivity, a flexural conductivity reference table is constructed.
[0035] In a preferred embodiment of the present invention, the flexural conductivity is a quantitative indicator reflecting the change in the electrical performance of a cable under bending conditions, and can reflect the differences in the electrical performance of the cable under different bending stresses. By testing the flexural conductivity at different bending angles in the laboratory and analyzing the mechanical state of the cable during bending using COMSOL modeling, the flexural conductivity corresponding to different bending angles can be obtained.
[0036] By analyzing the flexural conductivity at different bending angles and combining it with known patterns of cable aging, the relationship between cable aging and flexural conductivity is determined. Generally, as cables age, the flexural conductivity gradually decreases; that is, the smaller the flexural conductivity, the more severe the aging. Therefore, the degree of cable aging can be assessed based on the changing pattern of the flexural conductivity. A low flexural conductivity usually indicates that the cable has already exhibited significant aging. During field testing, if the measured flexural conductivity is lower than a set threshold, such as 70% of the initial value, the cable is determined to have entered a significant aging stage, and an alarm is issued.
[0037] See Figure 2 This is an embodiment of the present invention that provides a submarine cable aging detection device based on flexural electrical effect, comprising: a calculator 1, an oscilloscope 2 and a charge amplifier 3; The input terminal of the charge amplifier 3 is connected to the submarine cable 4 under test, the input terminal of the oscilloscope 2 is connected to the output terminal of the charge amplifier 3, and the input terminal of the calculator 1 is connected to the output terminal of the oscilloscope 2; wherein the submarine cable 4 under test is in a power-off state; The charge amplifier 3 is used to receive the polarization charge generated by the submarine cable 4 under non-uniform strain and amplify the polarization charge. The oscilloscope 2 is used to receive the amplified voltage signal of the polarization charge and form a voltage waveform; The calculator 1 is used to obtain the structural parameters of the submarine cable; calculate the flexural conductivity of the submarine cable under test based on the voltage waveform and the structural parameters; determine the aging degree of the submarine cable under test based on the flexural conductivity, and issue an alarm when the aging degree is greater than a preset degree level threshold.
[0038] In a preferred embodiment of the invention, the metal conductors of the submarine cable 4 to be tested are connected by wires using an insulating piercing clamp or welding method, ensuring an electrical connection is established without damaging the cable insulation. The wires are connected to the input terminal of the charge amplifier 3, and the charge amplifier 3 is grounded. The charge amplifier amplifies minute charge changes caused by variations in the cable's electrical characteristics, providing necessary signal enhancement. The output terminal of the charge amplifier 3 is connected to an oscilloscope 2 or other waveform analysis equipment to capture the electrical response waveform of the cable under bending conditions in real time. Through waveform analysis, changes in the cable's electrical characteristics can be monitored in real time.
[0039] Based on the data displayed on oscilloscope 2, calculator 1 can calculate the flexural coefficient of the cable. According to the flexural effect theory, insulating materials generate polarization charges under non-uniform strain (such as bending). For a cylindrical cable structure, its flexural coefficient P can be expressed as: in, The polarization charge (C) caused by bending; The effective force-bearing area of the insulation layer (m²); is the dielectric constant of the insulating material (F / m); The strain gradient (m-¹) is along the bending direction.
[0040] Furthermore, the calculator 1 calculates the flexural conductivity of the submarine cable under test based on the voltage waveform and the structural parameters, including: Obtain the amplification gain coefficient of the polarization charge; Based on the voltage waveform, determine the voltage peak value, and calculate the polarization charge based on the amplification gain coefficient and the voltage peak value; The flexural conductivity of the submarine cable under test is calculated based on the polarization charge and the structural parameters.
[0041] Furthermore, the structural parameters include: the outer radius of the insulation layer of the submarine cable under test, the bending angle, the length of the bending section, and the dielectric constant of the insulation layer; The calculator 1 calculates the flexural conductivity of the submarine cable under test based on the polarization charge and the structural parameters, including: The strain gradient and effective stress area of the submarine cable under test are calculated based on the outer radius of the insulation layer, the bending angle, and the length of the bending segment. The flexural coefficient of the submarine cable under test is calculated based on the polarization charge, the dielectric constant, the strain gradient, and the effective stress area.
[0042] Furthermore, the calculator 1 determines the degree of aging of the submarine cable under test based on the flexural conductivity coefficient, including: Obtain a flexural conductivity comparison table; wherein, the flexural conductivity comparison table records the standard flexural conductivity of the unaged submarine cable under test at different bending angles; Based on the bending angle, the target flexural coefficient is determined by searching the flexural coefficient lookup table. The difference between the target flexural coefficient and the flexural coefficient is calculated, and the degree of aging of the submarine cable to be tested is determined based on the difference.
[0043] Furthermore, the construction of the flexural coefficient lookup table includes: Construct a simulation model of the submarine cable to be tested in its unaged state; In a simulation environment, the standard flexural conductivity of the simulation model at different bending angles is measured; Based on the bending angle and the corresponding standard flexural conductivity coefficient, a flexural conductivity coefficient reference table is constructed.
[0044] It is understood that the above-described device embodiments correspond to the method embodiments of the present invention, and can realize the above-described method embodiments of the present invention to provide a submarine cable aging detection method based on flexural electrical effect.
[0045] It should be noted that the device embodiments described above are merely illustrative, and some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, in the accompanying drawings of the device embodiments provided by this invention, the connection relationships between modules indicate that they have communication connections, which can specifically be implemented as one or more communication buses or signal lines. Those skilled in the art can understand and implement this without any creative effort.
[0046] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.
Claims
1. A method for detecting aging of a submarine cable based on flexoelectric effect, characterized in that, The method comprises the following steps: polarization charges generated by the to-be-detected submarine cable under non-uniform strain in a power-off state are acquired, and structural parameters of the to-be-detected submarine cable are acquired; the polarization charges are amplified, and a voltage waveform is formed according to a voltage signal of the amplified polarization charges; a flexoelectric coefficient of the to-be-detected submarine cable is calculated according to the voltage waveform and the structural parameters; an aging degree of the to-be-detected submarine cable is determined according to the flexoelectric coefficient, and an alarm is given when the aging degree is greater than a preset degree threshold.
2. A method of detecting the ageing of a subsea cable based on the flexoelectric effect according to claim 1, characterised in that, The method of calculating the flexoelectric coefficient of the to-be-detected submarine cable according to the voltage waveform and the structural parameters comprises the following steps: an amplification gain coefficient of the polarization charges is acquired; a voltage peak value is determined according to the voltage waveform, and a polarization charge quantity is calculated according to the amplification gain coefficient and the voltage peak value; the flexoelectric coefficient of the to-be-detected submarine cable is calculated according to the polarization charge quantity and the structural parameters.
3. A method of detecting the ageing of a subsea cable based on the flexoelectric effect according to claim 2, characterised in that, The structural parameters comprise an outer radius of an insulation layer of the to-be-detected submarine cable, a bending angle, a bending segment length, and a dielectric constant of the insulation layer. The method of calculating the flexoelectric coefficient of the to-be-detected submarine cable according to the polarization charge quantity and the structural parameters comprises the following steps: a strain gradient and an effective stress area of the to-be-detected submarine cable are calculated according to the outer radius of the insulation layer, the bending angle, and the bending segment length; the flexoelectric coefficient of the to-be-detected submarine cable is calculated according to the polarization charge quantity, the dielectric constant, the strain gradient, and the effective stress area.
4. A method of detecting the ageing of a subsea cable based on the flexoelectric effect according to claim 3, characterised in that, The method of determining the aging degree of the to-be-detected submarine cable according to the flexoelectric coefficient comprises the following steps: a flexoelectric coefficient reference table is acquired; the flexoelectric coefficient reference table records standard flexoelectric coefficients of a non-aged to-be-detected submarine cable under different bending angles; a target flexoelectric coefficient is determined by searching the flexoelectric coefficient reference table according to the bending angle; a difference between the target flexoelectric coefficient and the flexoelectric coefficient is calculated, and the aging degree of the to-be-detected submarine cable is determined according to the difference.
5. A method of detecting the ageing of a subsea cable based on the flexoelectric effect according to claim 4, characterised in that, The construction of the flexoelectric coefficient reference table comprises the following steps: a simulation model of the to-be-detected submarine cable in a non-aged state is constructed; standard flexoelectric coefficients of the simulation model under different bending angles are measured in a simulation environment; a flexoelectric coefficient reference table is constructed according to the bending angles and the corresponding standard flexoelectric coefficients.
6. A device for detecting aging of a submarine cable based on flexoelectric effect, characterized in that, The method comprises the following steps: a calculator, an oscilloscope, and a charge amplifier are provided; an input end of the charge amplifier is connected to a to-be-detected submarine cable, an input end of the oscilloscope is connected to an output end of the charge amplifier, and an input end of the calculator is connected to an output end of the oscilloscope; wherein the to-be-detected submarine cable is in a power-off state; the charge amplifier is used for receiving polarization charges generated by the to-be-detected submarine cable under non-uniform strain and amplifying the polarization charges; the oscilloscope is used for receiving a voltage signal of the amplified polarization charges and forming a voltage waveform; and the calculator is used for calculating a flexoelectric coefficient of the to-be-detected submarine cable according to the voltage waveform. The calculator is configured to: acquire a structure parameter of the submarine cable; calculate a flexoelectric coefficient of the submarine cable to be detected according to the voltage waveform and the structure parameter; determine an aging degree of the submarine cable to be detected according to the flexoelectric coefficient, and issue an alarm when the aging degree is greater than a preset degree threshold.
7. A flexoelectric effect based cable ageing detection apparatus as claimed in claim 6, wherein, The calculator is configured to calculate a flexoelectric coefficient of the submarine cable to be detected according to the voltage waveform and the structure parameter, including: acquiring an amplification gain coefficient of the polarization charge; determining a voltage peak value according to the voltage waveform, and calculating a polarization charge amount according to the amplification gain coefficient and the voltage peak value; calculating the flexoelectric coefficient of the submarine cable to be detected according to the polarization charge amount and the structure parameter.
8. A flexoelectric effect based cable ageing detection apparatus as claimed in claim 7, wherein, The structure parameter includes an outer radius of an insulation layer of the submarine cable to be detected, a bending angle, a bending segment length, and a dielectric constant of the insulation layer. The calculator is configured to calculate the flexoelectric coefficient of the submarine cable to be detected according to the polarization charge amount and the structure parameter, including: calculating a strain gradient and an effective stress area of the submarine cable to be detected according to the outer radius of the insulation layer, the bending angle, and the bending segment length; calculating the flexoelectric coefficient of the submarine cable to be detected according to the polarization charge amount, the dielectric constant, the strain gradient, and the effective stress area.
9. A flexoelectric effect based cable ageing detection apparatus as claimed in claim 8, wherein, The calculator is configured to determine the aging degree of the submarine cable to be detected according to the flexoelectric coefficient, including: acquiring a flexoelectric coefficient reference table, wherein the flexoelectric coefficient reference table records standard flexoelectric coefficients of the submarine cable to be detected in different bending angles under a non-aging state; searching the flexoelectric coefficient reference table according to the bending angle to determine a target flexoelectric coefficient; calculating a difference between the target flexoelectric coefficient and the flexoelectric coefficient, and determining the aging degree of the submarine cable to be detected according to the difference.
10. A flexoelectric effect based cable ageing detection apparatus as claimed in claim 9, wherein, The construction of the flexoelectric coefficient reference table includes: constructing a simulation model of the submarine cable to be detected in a non-aging state; measuring standard flexoelectric coefficients of the simulation model in different bending angles in a simulation environment; constructing a flexoelectric coefficient reference table according to the bending angles and the corresponding standard flexoelectric coefficients.